Research On The Relationship Between Friction Heat And Thermal Stress And Strain Of Wheel-rail Contact Spots In Normal Operation

In recent years,with the continuous development of my country’s economy,the railway system has also developed rapidly.Various policies to promote the accelerated development of the railway system have also been introduced,and the railway system has continued to develop towards high speed and heavy load.Previously,Hertz contact theory was widely used in the field of wheel-rail contact research,but due to its own limitations,it performed poorly in revealing the true state of wheel-rail contact.The development and utilization of large-scale simulation software has solved this problem well.Through the use of simulation software,the change of wheel-rail contact status can be more realistically reflected,which provides an important reference for scientific research on high-speed railways.In view of the wheel-rail contact characteristics of high-speed railways without lateral movement,the ABAQUS simulation software is used to establish a thermal-structure directly coupled three-dimensional wheel-rail contact model.The wheel-rail contact simulation is mainly based on the dynamic-structure-temperature direct coupling dynamic theory,using ABAQUS’s Explicit solution module to simulate the wheel-rail contact,solving the wheel-rail contact spot temperature,stress and strain values,and analyzing the coupling relationship Research and draw the following conclusions:(1)At different times of normal train operation,under the same axle load,friction coefficient and convective heat transfer coefficient,under the thermal-structural coupling of wheel-rail frictional heat and wheel-set mechanical load,the wheel-rail stress and strain will follow the wheel-rail contact spot.When the friction temperature rises,it first drops and then rises.In summary,under the normal working conditions of the train,under the thermal-structural coupling effect of the wheel-rail,the stress and strain and the wheel-rail contact spot friction heat are firstly negatively correlated,and then positively correlated.(2)When the friction coefficients between wheels and rails are different,under the same axle load and convective heat transfer coefficient,during normal train operation,under the thermal-structural coupling of wheel-rail frictional heat and wheel-set mechanical load,the rail stress follows the wheel-rail contact spot friction temperature rises and rises,strain first drops and then rises;wheel stress and strain both rise with the rise in friction temperature of wheel-rail contact spots,and the rise is basically the same.In summary,under the normal working conditions of the train,under the thermal-structural coupling,the rail stress and the wheel-rail contact spot friction heat are positively correlated,and the strain and the wheel-rail contact spot friction heat are first negatively correlated and then positively correlated;Wheel stress,strain and wheel-rail contact spot friction heat are positively correlated.(3)When the convective heat transfer coefficient between the wheel and the air is different,under the same axle load and friction coefficient,when the train is running normally,under the thermal-structural coupling action of the wheel-rail friction heat and the wheelset mechanical load,the rail stress follows the wheel-rail The friction temperature of the contact spots increases,and the strain decreases with the increase of the friction temperature of the wheel-rail contact spots;the stress and strain of the wheel both increase with the increase of the friction temperature of the wheel-rail contact spots.In summary,under the normal working conditions of the train,under the thermal-structural coupling,the rail stress has a positive correlation with wheel-rail contact patch friction heat,and the strain has a negative correlation with wheel-rail contact patch friction heat;wheel stress and strain have a positive correlation with wheel-rail contact patch friction heat;The frictional heat of wheel-rail contact spots is positively correlated.